“location” directive should be inside a ‘server’ directive, e.g.
server {
listen 8765;
location / {
resolver 8.8.8.8;
proxy_pass http://$http_host$uri$is_args$args;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}